Core drilling apparatus



2 SHEETS- SHEET 1 J. c. sToKEs R- O, w n N l March 31, 1953 CORE:DRILLING APPARATUS Filed Dec. 13, -194s f m. A f

Malh 31, 1953 '.1. c. s'roKEs CORE DRILLING APPARATUS 2 SHEETS-SHEET 2Filed Dec. 13, 1 948 Patented Mar. 31, 1953 CORE DRILLING APPARATUS JohnC. Stokes, Houston, Tex., assignor to Reed Roller Bit Company, Houston,Tex., a corporation of Texas Application December 13, 1948, Serial No.64,923

8 Claims.

This invention relates to new and useful improvements in core drillingapparatus and particularly to an improved closure for closing the lowerend of the core barrel during lowering of the apparatus within a wellbore.

As is well known, it has become the general practice in core drillingapparatus to provide a plug or closure for closing the lower end of thecore barrel during lowering of the apparatus into position. Usually thisplug is mounted in position by frangible or f rictional means so that apredetermined pressure against its lower end, usually by imposition ofthe weight of the drill string thereon, releases the plug to allow it tomove upwardly within the core barrel in advance of the core. These plugsare effective to close the core barrel until coring begins but have nomeans for cleaning out the bottom of the bore prior to the coringoperation.

In more recent years, coring in harder formations is being accomplishedwith diamond bits which are constructed with diamond chips or particlesembedded in the cutting face, such bits being employed not only for borehole drilling but also for coring operations. It has been found thatduring a drilling or coring operation, some of the diamonds may becomedetached from the cutting face of the bit falling to the bottom of thebore and it is obviously desirable to recover said diamond. Also, junkin the form of various metallic pieces which may have broken off fromthe pipe couplings or tools may be present in the bottom of the borehole and it is desirable that this junk be removed prior to a coringoperation.

It is, therefore, one object of this invention to provide an improvedclosure for the lower end of a core barrel which closure constitutes acombined plug and fishing basket, whereby any material which may bepresent in the bottom of the well bore may be recovered prior to thecoring operation and before the closure is moved upwardly out of itsbarrel-closing position.

An important object of the invention is to provide an improved corebarrel closure which has a. receptacle in its lower portion and whichhas means for circulating the usual drilling uid through and around saidreceptacle, whereby any material, such as diamonds, which may be presentin the bottom of the bore hole will ush into the receptacle and bethereby recovered when the closure is ultimately brought to the surfacewith the core barrel; the mounting of said c losure in the lower portionof the core barrel being such that the pressure of the circulatingdrilling or ushing fluid maintains said closure in position, closing thecore barrel during the flushing operation.

Another object of the invention is to provide.

an improved combination plug and shing basket, of the characterdescribed, having means for assuring a circulation of the ushing iiuidbeneath the device when said device is at the bottom of the well bore,whereby removal of all extraneous material in the bottom of said wellbore is accomplished.

A further object of the invention is to provide an improved combinedplug and fishing basket which is particularly adapted for use inconjunction with a diamond core drill.

The construction designed to carry out the invention will be hereinafterdescribed together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawings,wherein an example of the invention is shown, and wherein:

Figure 1 is a transverse, vertical sectional view of the improvedclosure, showing the same mounted within the lower end of thecore-taking apparatus,

Figure 2 is a horizontal, cross-sectional view,

taken on the line 2-2 of Figure 1,

Figure 3 is a view, partly in section and partly in elevation, of amodified form of closure, and

Figure 4 is a horizontal cross-sectional View, taken on the line 4 4 ofFigure 3.

v In the drawings, the letter A designates the improved combined plugand iishing basket which is illustrated as combined with a diamond corebit I0, although it is to be understood that the device A may beemployed with any coretaking apparatus. The diamond core bit I0 has theusual internally threaded box II at its upper end, whereby the bit maybe connected to the lower end of an outer core barrel I2. As is wellknown, the barrel I2 is connected with the drill pipe, whereby arotation may be imparted to the core bit I0. The core bit is formed witha central or axial bore I3 and the intermediate portion of the bore isinclined to provide a tapered core catcher seat I4 and a split corecatcher I5 engages this seat. As is illustrated in Figure 2, the corecatcher I5 comprises a split sleeve having a plurality of axial grooves`I6 in its outer surface. Drilling iiuid circulated downwardly throughthe core barrel I2 may pass through the grooves or recesses I 6 in thecore catcher and then downwardly through circulating passages I'I whichextend through the body of the core bit. The cutting surface I8 of thebit is disposed at the lower end thereof and includes the usual diamondswhich are embedded in said cutting surface. An inner core barrel I9 ismounted within the outer barrel I2 and has its lower end axiallycentered by means of spacing ribs 20. Usually, the inner barrel I9 isrotatably mounted with respect to the outer barrel I2.

The improved closure A comprises a tubular body 2I having a bore 22extending entirely therethrough. An external shoulder 23 is formed atthe upper portion of the tubular body 2I and this shoulder is adapted toengage the upper end of the core catcher I5, whereby the body 2| will besupported within the core bit. The body is of such length that when theshoulder 23 is in engagement with the core catcher I5, the lower portionof the body 2| projects downwardly in advance of the core bit.

A transverse partition 24 is welded or otherwise secured across theupper portion of the bore 22 and this partition or plate substantiallycloses the upper end of the bore. A fluid conducting tube 25 has itsupper end secured within the partition 24 and extends axially throughthe tubular body 2I. The lower end of the tube is suitably fastenedwithin a bottom closure plate 26 which is welded or otherwise secured inthe lower end of the bore 22 of the body 2I. The tube 25 has its upperend communicating with the area above the upper partition 24, and itslower end communicates with the space below the bottom plate 25. Fluidwhich is circulated downwardly through the core barrel I2 may enter theupper end of the tubular body 2I above the partition or plate 24 throughinclined inlet ports 21 which extend through the wall of the body. Inthis manner, fluid circulated downwardly through the drill pipe andouter barrel I2 will be directed into contact with the plate 24 and mayflow downwardly through the circulating tube 25 to escape from the lowerend thereof vbeneath the bottom plate 26 of the device. The pressureacting against the upper plate 24 will functionv to maintain the deviceA in its lowered position with the supporting shoulder 23 engaging thecore catcher I5.

To permit a free circulation of the fluid flowing downwardly through thetube 25 beneath the device A, the bottom plate 26 which closes the lowerend of the tubular body ZI is provided with downwardly extending lugs orcleats 28 and obviously, these lugs will prevent the bottom plate 26from resting on the bottom of the well bore within which the apparatusis lowered. This will assure a free circulation of the fluid beneath thedevice. For receiving the material which will be dislodged from thebottom of the well bore upon a circulation of iluid downwardly withinthe lower end of the bore, the tubular body 2I is formed with aplurality of enlarged inlet openings 29. As is clearly shown in Figurel, these openings are spaced around the body and are at a point spacedabove the bottom 2S whereby a chamber or receptacle 30 is formed in thebottom of the body 2 I.

In the operation of the device, the same is positioned within the corebit I as illustrated in Figure 1, and the core-taking apparatus islowered downwardly through the well bore. During the lowering movement,the device A functions to close the lower end of the inner core barrelI9 to prevent the admission of drilling mud or other material into saidbarrel. The frictional engagement of the core catcher I5 with the outerwall of the tubular body 2| of the device will be ordinarily sufficientto maintain said device in position closing the lower end of saidbarrel. However, if desired, a shear pin or additional frictional meanscould be provided to assure that the device A will not move upwardlywithin the core barrel during the lowering operation. Upon reachingbottom, the lugs or cleats 2B will strike the bottom of the well bore,and at this time a ushing fluid which may be the ordinary drilling fluidis circulated downwardly through the drill pipe and outer barrel I2. Asexplained, this fluid will pass downwardly through the inclined ports 21in the upper portion of the body 2i and will act against the upperpartition or plate 24 to urge the device A downwardly and therebymaintain it in the position shown in Figure 1. A portion of the uidwill, of course, circulate downwardly through the circulating tube 25and will escape beneath the bottom 2S of the device. The drilling fluidwill also circulate downwardly through the circulating passages i? ofthe bit and by controlling the pressure of the circulating fluidat thispoint, a turbulent or swirling action sufficient to wash the materialwhich may have accumulated in the bottom or" the well bore upwardly intothe stream may be obtained. If the material consists of diamonds whichmay have been lost dur-- ing a preceding drilling operation, theswirling or turbulent action of the fluid will flush said diamondsupwardly into the inlet openings 29 of the device A and said diamondswill, of course, fall downwardly into the receptacle 35 at the lower endof said device. junk which may be present in the bottom of the well borewill also be agitated and washed upwardly into the receptacle 30.

After the ilushing operation is complete, the drill pipe and bit I0 maybe lowered to carry out the coring operation and at this time, thedevice A will move upwardly into the inner core barrel I9 in the usualmanner. When the core has been taken and the apparatus removed, it willbe evi-v dent that any material within the receptacle 3|] may berecovered when the device A is removed from the inner core barrel.

A modified form of the invention is illustrated in Figures 3 and 4,wherein a combined plug and fishing basket A includes a cylindrical body3I having a bore 32. The lower portion of the bore 32 is reduced asindicated at 33 to provide a circulating fluid passage through the body.In

clined ports 21a are formed in the upper portion of the body 3l above anexternal supporting shoulder 23a. Fluid circulated downwardly throughthe core barrel when the device A is in position within the core bit I3will flow downwardly through the ports 2'ia and through the bore 32 andreduced passage 33 to escape from the lower end of said passage belowthe device.

Lugs or cleats 23a are secured to the bottom of the body 3l and functionin the same manner as the lugs or cleats 28 of the rst form.

The lower portion of the body 3l is formed with an annular recess 3c anda sleeve or collarv 35 which is secured to the body encircles the lowerportion of this recess, whereby a receptacle 3S is formed within saidcollar or sleeve. A plurality of wings or ribs 3'1 are disposed withinthe upper portion of the recess 34 and each of said.

Any other material or wings is formed with an offset or shoulder 33which engages the upper end of the collar or sleeve 35. The spacesbetween the radially extending wings 97 provide inlet openings, wherebymaterial which is ushed upwardly from the bottom of the well bore mayenter the annular receptacle 39 in the lower portion of the device A. Itwill be apparent that the modification shown in Figures 3 and l operatesin exactly the same manner as the device A of the iirst form.

The invention provides a simple and eicient means for closing the lowerend of the core barrel i9 during lowering ci the apparatus within thewell bore. At the same time, the 'fishing basket which is formed as apart of the closure makes it possible to recover r remove diamonds, junkor other material which may have accumulated in the bottom of the wellbore.

The foregoing description of the invention is explanatory thereof andvarious changes in the size, shape and materials, as well as in thedetails of the illustrated construction may be made, within the scope ofthe appended claims, without departing from the spirit of the invention.

Having described the invention, I claim:

1. The combination with a core-taking apparatus having a core bit and acore-receiving barrel, of a closure device including, a body having itsupper portion mounted within the core bit with the lower portionextending downwardly in a plane below the bit, a transverse closureextending across the body, a receptacle in the lower portion of the bodybelow the closure, said receptacle havingr its upper end open to thewell bore within which the apparatus is lowered and means eX- tendinglongitudinally through the closure and body for circulating a flushingfluid downwardly through the body and through the transverse closure inthe body as well as exteriorly thereof to ilush any loose material whichmay be present in the well bore into the receptacle.

2. The combination with a core-taking apparatus having a core bit and acore-receiving barrel, of a closure device including, a body having itsupper portion mounted within the core bit with the lower portionextending downwardly in a plane below the bit, a receptacle in the lowerportion of the body, said receptacle having its upper end open to thewell bore within which the apparatus is lowered, means for circulating aflushing iiuid downwardly through the body and also exteriorly thereofto flush any loose material which may be present in the well bore intothe receptacle` and means for utilizing the iiuid pressure to hold thebody in position within the bit during the ushing operation.

3. A closure device for core-taking apparatus including, a cylindricalplug member having an axial bore extending entirely therethrough withthe lower portion of said bore being reduced to form a restricted flowpassage, the exterior lower portion of the body being formed with anannular recess, and a sleeve secured to the body and encircling thelower end of the annular recess to form an annular receptacle at thelower portion of the plug member.

4. The combination with a core-taking apparatus having a core bit and acore-receiving barrel, of a closure device adapted to be mounted withinthe core bit and comprising a combined plug and shing basket, said shingbasket being disposed at the lower end of the plug and having an openupper end for receiving foreign material, said open upper end of thefishing basket being located in a plane below the core bit when theclosure device is mounted within said core bit and means extendinglongitudinally through the plug and basket for conducting a iiuiddownwardly through the device and for ejecting said fluid into the areabelow said basket.

5. A closure device for core-taking apparatus including, a body having aclosed upper end and a central fluid passage therethrough and insertablewithin the bore of the core-taking apparatus, and an annular receptaclewithin the lower portion of the body, said receptacle having its upperend open to receive foreign material from exteriorly of the body, saidopen upper end of the receptacle being located in a plane below the boreof the core-taking apparatus when the body is within the bore.

6. A' closure device for core-taking apparatus comprising, a cylindricalplug member insertable within the bore of the core-taking apparatus, anda receptacle secured to the lower portion of the member, said receptaclebeing in communication through enlarged openings with the areaexteriorly of the member, said enlarged openings being disposed in aplane below the bore of the core-taking apparatus when the plug memberis within said bore.

7. A closure device for core-taking apparatus comprising, a cylindricalplug member insertable within the bore of the core-taking apparatus, anda receptacle secured to the lower portion of the member, the upper endof said receptacle being in communication through enlarged openings withthe area exteriorly of the member, the enlarged openings being disposedin a plane below the bore of the core-taking apparatus when the plugmember is disposed therein, said member and receptacle having a fluidpassage extending entirely therethrough, whereby fluid may be circulateddownwardly through the member to the area therebelow.

8. A closure device for core-taking apparatus comprising, a cylindricalplug member, a receptacle secured to the lower portion of the member,the upper end of said receptacle being in communication through enlargedopenings with the area exteriorly of the member, the enlarged openingsbeing disposed in a plane below the bore of the core-taking apparatuswhen the plug member is disposed therein, said member and receptaclehaving a i'luid passage extending entirely therethrough, whereby fluidmay be circulated downwardly through the member to the area therebelow,and means on the underside of the receptacle for engaging the bottom ofa well bore to space the underside of said receptacle from the bottom ofthe bore to assure circulation of fluid beneath said receptacle.

JOHN C. STOKES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 470,593 Oxley Mar. 8, 1892587,779 Barker Aug. 10, 1897 1,525,235 Hansen Feb. 3, 1925 1,784,886Baker Dec. 16, 1930 1,819,484 Scott Aug. 18, 1931 2,238,609 Sewell Apr.15, 1941 2,304,482 Simons Dec. 8, 1942

